Cellulose-xanthating process



CELLULOSE XANTHATING PROCES S Filed May l, 1926 2l Ha. l

1 Z0 4 A ,i525 7 a 25 Patentedr Aug, 2l, 1928.

UNITED STATES PATENT oFFlcE.

WILLIAM MENDE, F BEVERLY, NEW' JERSEY, ASSIGNOR T0 SAMUEL A. NEIDICH,

' AOF EDGEWATER PARK, NEW JERSEY.

CELLULOSE-XANTHATIN G PROCESS.

Application led May 1,

My invention may be employed with particular advantage in the manufacture of viscose, which is variously known as cellulose sulphocarbonate or cellulose thiocarbonate.

5 Such viscose is conveniently produced by subjecting comminuted wood to the action of an aqueous solution of sodium hydroxide, which separates the lignone from the cellulose, so that it may be withdrawn with such aqueous solution, leaving what is known to the trade as alkali-cellulose or crumbs. Such alkali-cellulose crumbs are then sub1 n ected to the action of carbon bisulphide, CS2,

to produce cellulose xanthate, and my invention relates particularly to steps in the process preceding and following such CS2 reaction. y

Such crumbs normally contain not only a large percentage of' uncombined water, -but considerable atmospheric air which, of course,

contaminate the carbon bisulphide applied thereto, and weaken the action thereof. However, kit is the usual practice to proceed to subject masses of such alkali-cellulose crumbs to the action of carbon bisulphide, in any suitable container, without any attempt to eliminate the occluded air and wat-er from such masses, with the consequence that the reaction is correspondingly retarded.

Therefore, it is an object and effect of my invention to facilitate the CS, reaction by eliminating such surplus moisture and occluded air from the cellulose crumbs before subjecting the same to the action of carbon bisulphide and with the advantage that the crumbs are thereby rendered more porous and receptive to the carbon bisul hide and the latter is not contaminated or diluted by such air and moisture. Moreover, after the ordinary xanthating process aforesaid has effected the desired action upon the cellulose, the latter is liable to deteriorate by further action of the carbon bisulphide remaining occluded in the mass and, upon opening the container, the carbon bisulphide yfumes thus liberated may explode and, in any event, are unhealthful and dangerous to the operator.

rlherefore, a further object and effect of my invention istoeliminate all surplus carbon bisulphide fumes from the mass of sodium xanthate, when the latter reaches the desired stage and before exposing the same to the atmosphere.

rlhe advantages aforesaid are attained, in accordance with my invention, by secluding a mass of such crumbs and subjecting them to 1926. Serial No. 106,155.

a partial vacuum until the occluded air and water vapor are evacuatedtherefrom, before `subjecting such crumbs to the action of carfeatures of procedure hereinafter more definitely specified.

ln said drawings; Fig. I is a diagrammatic plan view of apparatus which may be conveniently employed in effecting my process.

Fig. Il is a vertical sectional view of the rotary churn indicated in Fig. I, but on a larger scale.

In said figures; the churn l conveniently includes a hexagonal tubular body having an opening 2 in one side thereof provided with the removable cover 3 which may be hermetically secured thereon by any convenient means, to temporarily close the chamber t in said churn and exclude the same from the outer atmosphere. Said churn includes the opposite end closures 5 and 6, which are provided with respective stuffing boxes 7 and 8, and is mounted to rotate upon the 'tubular shaft 9 which is perforated at 10 and is held in stationary position in the standards il and 12, by the set screws 13. Said churn is held in predetermined axial position on said shaft 9 by the collars 14 and 15 which are respectively rigidly, but detachably, connected with said shaft 9 adjacent to said closures 5 6.

Said churn l may be rotated by any convenient means, forinstance by the belt l? which encircles the pulley 18 which is rigidly v connected with said end closure 6.. Said shaft 9, which may be a commercial size wrought iron pipe, is operatively connected, by the elbow 19, with the exhaust pipe 2C', which may be opened and closed by the valve 2l and extends in communication with any suitable evacuating means capable of prodnc- `k L ing a partial vacuum in the chamber of churn; for instance the vacuum pump Said 'tubular shaft 9 is also connected the pipe 25 which is arranged to be open and closed by lthe valve 26 and extends to suitable source of carbon bisulphide, for instance the container 27.

rlhe apparatus above described may be utilized to eect my process as follows: Said cover 3 being removed, a mass or' alkali-oeh lulose BO may be deposited in said chamber l through. said churn opening 2 and said cover 3 be replaced in fluid tight relation with said churn l. Said valve 26 being closed and said valve 2l opened; said chamber 4 may be evacuated by suction upon pipe 20, While said mass 30 is agitated in said chamber a by rotation ot the churn 1 by said belt 17. Said churn l is `conveniently provided with the gauge 3l indicating the pressure of the atmosphere in said chamber l and, when it indicates that the secluded and confined at mosphere in said chamber has been evacuated to the desired degree; said valve 2l may be closed and said valve 26 opened to introduce carbon bisulphide to said chamber.

As above contemplated, the evacuation ot said chamber d and its contents, While in communication with the vacuum pump 23, or other suitable means, notonly removes the air normally occluded in the mass of crumbs 30 and deprives the latter of the residual moisture remaining from previous treatment thereof, but thus renders said crumbs porous and abnormally receptive to the action ot said carbon bisulphide which reactslwith the oomniinication between said churn chamber A and the evacuating means 23. The fumes of carbon bisulphide are thus not only quickly exhausted rom said churn chamber l but also removed from the mass of Xanthate then result-ing from the reaction aforesaid upon said crumbs 30.` Consequently, said churn closure 3 may be removed to permit the Xanthate to be discharged trom said chamber Il, Without any danger ot explosion or discomfort to the operator. Thereupon, the

reagent CS2 to do operation above described may be repeated., As above contemplated; my invention is characterized by two distinct features; Erst, l have discovered that occluded Water vapor 'and air mechanically limit the penetration of carbon bi-sulphide-vapors, with respect to alkali cellulose crumbs, in the reaction to ormranthate, and that the ,reaction is etected more rapidly and completely such air and vapor are moved to permit the ,Jork in the interior CS2, While agita neaneoo of the mass. Second, that upon completion of such reaction; immediately evacuating the umes of CS2 from said mass, Without opening the container, has three important advantages, to Wit, deterioration ot thecellulose which is the inevitable consequence oi continuance it the reaction, is prevented; the liability to explosion incurred by opening the container to liberate said fumes is obviated; and the incident menace to the health oit the operator by inhalation oi such fumes is avoideda Although l have found it convenient to einploy apparatus constructed and arranged as above described, it is obvious that such apparatus is not essential tdedect my improved process Therefore, ll do not desired to limit myself to the precise details of construction, arrangement, or procedure above set forth, as it is obvious that various modifications may be made therein Wit-hout departing from the essential features ot my inventlon as delined in the appended claims.

l claim: v

1. A cellulose Xanthating process, which includes subjecting a mass ot alkali-cellulose to a vacuum",'while agitating said mass, until air, and Water vapor are exhausted therefrom; then subjecting said evacuated mass to the action of carbon bisulphide, While agitating said mass, until it is transformed to cellulose Xanthate; then subjecting said mass to the action of a vacuum, While agitating said mass, until the fumes or carbon bisulphide are eX- hausted therefrom. A

2. A cellulose Xanthating process, which includes subjecting a mass of alkali-cellulose to a vacuum,-until air and Water vapor are exhausted therefrom; then subjecting said evacuated mass to the action ot carbon bisulphide, until it is transformed to cellulose Xanthate; then subjecting said mass to the action of a vacuum, until the fumes of carbon bisulphide are exhausted therefrom.

3. A cellulose Xanthating process, which includes subjecting a mass ot alkali-cellulose to the action of carbon bisulphide, `While agitating said mass, until it is transformed to cellulose Xanthate; then subjecting said mass to the action of a vacuum, While agitating said mass, until the tumeslof carbon bisul phide are exhausted therefrom.

d. A cellulose ranthating process, which includes subjecting a mass of alkali-cellulose to the actionl of carbon loisulphide, until it is transformed to cellulose aanthate; then sub jecting said mass to the action ol a vacuum,

until the fumes o carbon bisulphide are en hausted theretrom.

5. A cellulose ranthating process which includes transforming a mass of alkalicellulose to cellulose `nanthate in a confined lGI) reactive chemical, atmosphere cor-taining` ting said mass; 'then ellpflst ing said chemical atmosphere from said ase,

Lesmo@ before exposing seid mass to the outer normal atmosphere.

i 6. A cellulose xanthating process which includes transforming a mass of alkali-cellulose to cellulose xanthate in a confined, reactive chemical7 atmosphere containing CS2; then exhausting said reactive chemical atmosphere from said mass, before exposing said mass to the outer normal atmosphere.

7. A cellulose xanthating process which includes transforming a mass of alkali-cellulose to cellulose xanthate in a conlined chemical atmosphere containing all of the reactive Inaterial capable of effecting such transformation; then exhausting said chemical atmosphere from said mass, before exposing said mass to the outer normal atmosphere; and recovering the chemical value o said atmosphere for subsequent use.

ln testimony whereof, l have hereunto signed my nume ut Burlington7 New Jersey, this 27th day of April, 1926.

llLLAM MENDEL. 

